The invention relates to an information transfer system, comprising a receiver, and a transmitter for transferring an information signal to the receiver via a transfer medium. The information signal comprises main data and sub data, the sub data comprising a coded text line having a plurality of character codes. The receiver is provided with a character display unit for displaying characters defined by the character codes in the coded text line, which display unit has a predetermined number of character display positions The invention further relates to a transmitter, a receiver and a record carrier for use in the system.
A system as described in the opening paragraph is known from EP-A-0,325,325. In that patent application, a system is described in which an information signal is transferred via a record carrier, for example, a Compact Disc or a digital audio tape, to an audio player. The player is provided with at least one multi-line display unit for displaying text lines defined by coded text lines included in the sub data transferred. The number of character positions (i.e., digits) of the display unit is sufficient to display a full text line of forty characters. By means of the system, additional information related to the main (audio) information reproduced can be displayed.
Full line display units are undesirable for use with systems of the type described above when small sized receivers, such as, for example, portable players and car radios, are used in those systems, because, in general, there is not enough space available for such full line display units. Full line display units are also undesirable for use on remote controllers for receivers. On the other hand, it is desirable that additional information related to reproduced main information can be displayed on display units of small sized receivers and remote controllers.
It is an object of the invention to provide means which enable significant parts of text information available from the sub data to be shown on display units of small-sized receivers and remote controllers without the requirement of far-reaching amendments to the sub data format.
According to the invention, this object is achieved by a system of the type described in the opening paragraph being characterized in that the predetermined number of character positions of the display unit is less than the number of character codes in the coded text line, and the coded text line further includes control codes. The receiver for that system comprises a display control unit for controlling display of the characters corresponding to (i.e., defined by) the character codes included in the coded text line in dependence on the control codes.
In the system according to the invention, the information already available in the coded text line (included in the sub data) for displaying on a full line display unit, can also be used for display on a small sized display unit with a limited number of character positions. This has the advantage that the addition of coded text to the sub data for exclusive use in combination with a 1-line display with a limited number of digits is not required.
An embodiment of the system is characterized in that the receiver further comprises a unit for storing the coded text line in a memory, the control codes comprise horizontal scrolling control codes, and the display control unit is adapted to initiate, in response to the horizontal scrolling control codes, the display unit to horizontally scroll through the characters of the coded text line stored in the memory. By using a combination of a memory and a scroll function, presentation of the contents of a complete coded text line is possible.
A further embodiment of the system is characterized in that the receiver further comprises an entry unit for manually entering scroll commands, and the display control unit is adapted to control a horizontal scroll of the characters of the coded text line stored in the memory in dependence on the entered scroll commands. This embodiment has the advantage that the user can initiate a horizontal scroll of the characters of the coded text line stored in the memory each time he or she finds that desirable.
Further embodiments of the system are characterized in that the display control unit is adapted to cause the display unit horizontally scroll through the characters with a speed dependent on the scrolling control codes or the entered scrolling commands. These embodiments enable adaption of the scroll speed on specific circumstances.
Another embodiment of the system is characterized in that the control codes comprises marking codes for marking a portion of the character codes, and the display control unit includes a unit for selecting which of the characters are to be displayed on the display unit on the basis of the marking codes. This embodiment enables the presentation of the most significant words of a message on the display unit. Preferably the characters (i.e., character strings) to be displayed are placed between a start code and a pause code. In that event, it is preferred to use a system, characterized in that the display control unit is adapted to cause a space-type character to be displayed in response to a pause code, and prohibit display of a character in response to a start codes. This embodiment provides a very suitable separation (on the display unit) between different character strings which are defined by the coded text line.
A further embodiment of the system is characterized in that the sub data comprises text packets which each include a coded text line and additional control codes, certain of the text packets including an indicating control code indicating that text packet includes a coded text line with text information to be displayed on the display unit (with the limited display positions); and the receiver further comprises a unit for determining which of the text packets include an indicating control code, and a unit for supplying the certain text packets to the display control unit. By the use of the indicating code, the display control unit is prevented from making unnecessary searches in coded text lines which does not include characters to be displayed on the 1-line display unit with a limited number of digits.
A receiver, transmitter and record carrier which are usable with the above-described systems, receive, transmit and store, respectively, an information signal including sub data having a coded text line including character codes and control codes for controlling display of characters defined by the character codes. In addition, the receiver includes a character display unit having less character display positions than there are character codes in a coded text line.